Add option to list network interfaces

ethsock.c

@@ -153,7 +153,7 @@ struct ethsock *ethsock_create(const char *interface, uint16_t protocol)
 
 	sock->pcap = pcap_open_live(interface, BUFSIZ, 1, 1, buf);
 	if (!sock->pcap) {
-		fprintf(stderr, "%s\n", buf);
+		fprintf(stderr, "%s.\n", buf);
 		goto cleanup_malloc;
 	}
 
@@ -261,3 +261,31 @@ int ethsock_set_timeout(struct ethsock *sock, unsigned msec)
 	sock->timeout.tv_usec = (msec % 1000) * 1000;
 	return 0;
 }
+
+int ethsock_list_all(void)
+{
+	pcap_if_t *devs, *dev;
+	uint8_t hwaddr[8];
+	char errbuf[PCAP_ERRBUF_SIZE];
+
+	if (pcap_findalldevs(&devs, errbuf) != 0) {
+		fprintf(stderr, "%s.\n", errbuf);
+		return -1;
+	}
+
+	for (dev = devs; dev; dev = dev->next) {
+		get_hwaddr(hwaddr, dev->name);
+		printf("%02x:%02x:%02x:%02x:%02x:%02x %s",
+				hwaddr[0], hwaddr[1], hwaddr[2],
+				hwaddr[3], hwaddr[4], hwaddr[5],
+				dev->name);
+
+		if (dev->description) {
+			printf(" (%s)\n", dev->description);
+		} else {
+			printf("\n");
+		}
+	}
+
+	return 0;
+}

ethsock.h

@@ -8,3 +8,4 @@ int ethsock_send(struct ethsock *sock, void *buf, size_t len);
 ssize_t ethsock_recv(struct ethsock *sock, void *buf, size_t len);
 int ethsock_set_timeout(struct ethsock *sock, unsigned msec);
 uint8_t *ethsock_get_hwaddr(struct ethsock *sock);
+int ethsock_list_all(void);

main.c

@@ -37,6 +37,7 @@ void usage(FILE *fp)
 			" -T <timeout>    Time to wait after successfull TFTP upload\n"
 			" -p <port>       Port to use for TFTP upload\n"
 			" -V              Print version and exit\n"
+			" -L              List network interfaces\n"
 			" -h              Show this screen\n"
 			"\n"
 			"Example:\n"
@@ -69,7 +70,7 @@ int main(int argc, char **argv)
 
 	opterr = 0;
 
-	while ((c = getopt(argc, argv, "a:f:i:m:M:p:t:T:hV")) != -1) {
+	while ((c = getopt(argc, argv, "a:f:i:m:M:p:t:T:hLV")) != -1) {
 		max = 0x7fffffff;
 		switch (c) {
 			case 'a':
@@ -109,6 +110,8 @@ int main(int argc, char **argv)
 			case 'V':
 				printf("nmrp-flash v%s\n", NMRPD_VERSION);
 				return 0;
+			case 'L':
+				return ethsock_list_all();
 			case 'h':
 				usage(stdout);
 				return 0;